This invention relates to unsymmetrical azo compounds, unsymmetrical hydrazo compounds, processes for preparing these compounds and processes utilizing these compounds, which azo and hydrazo compounds are characterized by having a tertiary carbon atom joined to one of the azo or hydrazo nitrogens.
Symmetrical azo compounds having a tert-carbon atom joined to each azo nitrogen are known:
T. e. stevens, J. Org. Chem. 26, 2531 (1961). PA1 E. farenhorst and E. C. Kooyman, Rec. Trav. China. 72, 993 (1953). PA1 S. f. nelson and P. D. Bartlett, J. Am. Chem. Soc. 88, 137, 143 (1966). PA1 M. c. chaco and N. Rabjohn, J. Org. Chem. 27, 2765 (1962). PA1 D. c. iffland, L. Salisbury, and W. R. Schafer, J. Am. Chem. Soc. 83, 747 (1961). PA1 D. y. curtin and J. A. Ursprung, J. Org. Chem. 21, 1221 (1956). PA1 C. g. overberger and A. V. Di Giulio, J. Am. Chem. Soc. 80, 6562 (1958); ibid 81, 2154 (1959). H. Wieland, et al, Ann. 514, 145 (1934). PA1 Thiele, B. 28, 2600. PA1 Angeli, Rome Atti Accad Tincei 26 I, 95 (1917). PA1 Thiele and Strange, Ann 283, 33 (1894). PA1 D. neighbors et al., J. Am. Chem. Soc. 44, 1557 (1922). PA1 2. R' is one of the following radicals: ##STR3## a. R.sub.1 and R.sub.2 are lower aliphatic or cycloaliphatic radicals and together may form an alkylene biradical, and R.sub.2 may also be phenyl or a substituted phenyl: PA1 b. R.sub.3 and R.sub.4 are hydrogen, lower aliphatic, or cycloaliphatic radicals and together may form an alkylene biradical; PA1 c. R.sub.5 is a lower aliphatic, cycloaliphatic or aromatic radical; PA1 d. R.sub.6 is a lower alkyl radical; PA1 e. R.sub.7 and R.sub.8 are hydrogen or lower alkyl radicals; PA1 f. R.sub.6 and R.sub.7 together may form an alkylene biradical; PA1 g. Z' is a zero, mono-, or di- valent remainder of a heterocyclic ring; PA1 h. Z is a radical; ##STR4## i. R.sub.12 is a biradical: ##STR5## j. Y" is a biradical: ##STR6## k. R.sub.13 is an aliphatic, cycloaliphatic, or aromatic biradical; l. X" is oxygen or sulfur; PA1 m. R.sub.10 is hydrogen, lower aliphatic, cycloaliphatic, or aromatic; PA1 n. R.sub.14 and R.sub.15 are ##STR7## PA1 b. R.sub.3 and R.sub.4 are hydrogen radicals and together may form an alkylene biradical. PA1 b. R.sub.1 and R.sub.2 are lower aliphatic or cycloaliphatic radicals and together may form an alkylene biradical. PA1 Reacting the R--NHNH.sub.2 acid salt with MCN and R.sub.1 --C(O)--R.sub.2 in water to form [B] above and oxidizing [B] to form the corresponding azo product. PA1 b. R.sub.1 and R.sub.2 are lower aliphatic or cycloaliphatic radicals and together may form an alkylene biradical, and R.sub.1 may also be phenyl or substituted phenyl; and PA1 c. X is chlorine, bromine, or iodine. PA1 a. M is an alkali or alkaline earth metal; PA1 b. Y is one of the following radicals: ##STR16## c. R, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.10, are as defined hereinbefore; PA1 d. Y" is one of the following biradicals: ##STR17## e. R'.sub.14 and R'.sub.15 are ##STR18## or --NO.sub.2 ; f. R.sub.13 in an aliphatic, cycloaliphatic or aromatic biradical and R'.sub.14 and R'.sub.15 are as defined hereinbefore; and PA1 g. X" is oxygen or sulfur. PA1 b. R.sub.3 and R.sub.4 are hydrogen, lower aliphatic or cycloaliphatic radicals and together may form an alkylene biradical; PA1 c. R.sub.9 is a lower alkyl radical; and PA1 d. R.sub.13 is an aliphatic, cycloaliphatic or aromatic biradical. 7. Fifth process; Preparation of azoacyl compounds. PA1 b. X is a chloro, bromo or iodo radical; and PA1 c. R.sub.13 is an aliphatic, cycloaliphatic, or aromatic biradical. PA1 b. Z' is a zero, mono, or divalent reminder of a heterocyclic ring; and PA1 c. X is chloro, bromo or iodo. PA1 b. X' is chloro, bromo, iodo, SO.sub.4 -- or HSO.sub.4 --. PA1 b. M' is a metal or hydrogen radical. PA1 Canadian Pat. No. 655,296 issued January 1, 1963. PA1 J. C. Bevington and A. Wahid, Polymer 3, 585 (1962); ibid 4, 129 (1963). PA1 D. neighbors, et al, J. Am. Chem. Soc. 44, 1561 (1922). PA1 H. zollinger, "Azo and Diazo Chemistry, Aliphatic and Aromatic Compounds", Interscience, New York, N.Y., 1961, p. 327. PA1 Goldschmidt and Acksteiner, Ann. 618, 173 (1958) British patent No. 988,253 issued Apr. 7, 1961 to Monsanto Co. PA1 Canadian Pat. No. 750,380 issued Jan. 10, 1967 to Monsanto Co. PA1 Y' is selected from the class consisting of: ##STR40## --OCN, --SCN, --SR.sub.5, and --OOR. PA1 H. bock and J. Kroner, Chem. Ber. 99, 2039 (1966). PA1 K. e. cooper and E. H. Ingold, J. Chem. Soc. 1926, 1894. ##STR45## It was unknown, prior to the present work, that a mono azo ester, such as [E], would react with primary and secondary amines (including ammmonia) to form the corresponding azoformamide. PA1 A. andraca, Anales quim farm 1941, p. 15. PA1 Pellizzari, Gass. chim. ital. 16, 302 (1888) PA1 Pinner, Ber., 20, 2359 PA1 Beilstein, 15, 287 PA1 C. vogelsang, Rec. trav. chim. 62, 5 (1943) PA1 K. a. taipale and P. V. Usachev, J. Russ. Chem. Soc. 62, 1241-58 (1930)
Unsymmetrical azo compounds where a tert-carbon atom is joined to one azo nitrogen are known. Illustrating compounds of this type, none coming within the scope of the invention are given in:
The above compounds are in general difficult to prepare, or are so stable that they are not useful as free radical generators or as blowing agents for plastic foams. 2,2'-azobisisobutyronitrile is commercially available. This compound has the structure ##STR1## It has many shortcomings. It is a toxic solid. Moreover, the decomposition residue is a highly toxic solid. Thus, it presents a toxic dusting problem when used in commercial operations and extreme precautions are required in its handling. It is not used in many applications for which it is suited because other areas at the manufacturing site cannot tolerate even the remote chance of exposure to such toxic dust. This is especially true when manufacturing goods for the food and drug packaging industries and many other goods for the household consumer. It cannot be used as a blowing agent for the great majority of the plastic foam market due to the high levels of the toxic residue left in the foamed product. It is insoluble in petroleum hydrocarbon solvents and possesses very low or limited solubility in most of the organic common solvents such as aromatic hydrocarbons, dioxane, alcohol, ether and carbon tetrachloride. This insoluble nature eliminates its use for many applications for which it would otherwise be suitable. It presents problems of metering, incorporation, mixing, dispersing etc. and necessitates the use of a solvent that in many cases is not ideally suited for the particular application.
The new compositions of the present invention eliminate these problems. Most of the new compositions are liquids and are soluble in petroleum hydrocarbon and most of the other common organic solvents. Thus, no dusting, metering, incorporating, mixing, and dispersing problems are encountered in using these new compositions. Also the new compositions and their decomposition residues have chemical structures that suggest that they are, for the most part, significantly less toxic. Preliminary toxicological studies on the new compositions made in Examples I and IV, set out later, and the decomposition residue of the Example I product indicate that they are significantly less toxic than IXA and its decomposition residue. The less toxic nature of the new compositions coupled with their liquid and high solubility properties allows them to be used in many applications where IXA cannot be used.
Unsymmetrical tert-carbon containing hydrazo compounds are known. Illustrative literature showing the prior art types of these compounds is presented: